Reduction kiln having distribution system

ABSTRACT

An apparatus is disclosed for delivering fuel and air to a rotary reduction kiln wherein both the fuel and air alternately flow through the same nozzle.

United States Patent 11 1 Rossi 1451 Nov. 12,1974

[ REDUCTION KILN HAVING DISTRIBUTION SYSTEM [75] Inventor:

[73] I Assignee: Allis-Chalmers Corporation,

Milwaukee, Wis.

[22] Filed: Oct. 1, 1973 [21] Appl. No.: 402,111

1 Related U.S. Application Data [62] Division of Ser. No; 302,606. Oct.31. 1972. Pat. No.

Eugene F. Rossi, Wauwatosu, Wis.

52 us. c1. 432/113, 432/26 51 1111.01. F27b 7/06, F27b 7/36 [58] Field01 Search..... 432/113, 105,103, 110.

[56] References Cited UNITED STATES PATENTS 2.063133 12/1936 Debuck432/105 Primary Examiner.lohn J. Camby Attorney, Agent, or Firm-John P.Hines [57] ABSTRACT An apparatus is disclosed for delivering fuel andair to a rotary reduction kiln wherein both the fuel and air alternatelyflow through the same nozzle.

4 Claims, 5 Drawing Figures 7 PATENT Hum 12 m4 E sum 1M 2 .3 .538

REDUCTION KILN HAVING DISTRIBUTION SYSTEM This is a division, ofapplication Ser. No. 302,606

filed Oct. 31, 1972, now U.S. Pat. No. 3,794,483.

This invention relates to rotary kilns used for such purposes asreducing iron ore to a lower state of oxidation having nozzles mountedon the outer surface of the kiln projecting radially through the kilnshell for injecting air and fuel into the kiln at axially andcircumferentially spaced locations along the kiln length. In particularthe invention relates to such a rotary kiln wherein the same nozzle canbe utilized to alternately provide both the fuel and the air to the kilncharge.

This application discloses subject matter similar to that disclosed inmy copending application Ser. No. 302,605 entitled Reduction Kiln Havinga Controllable Distribution System, filed Oct. 31, 1972, now US Pat. No.3,794,483.

In the prior art rotary kilns are known wherein a plurality of nozzlesare provided through the shell of the kiln to admit air and fuel into.the interior or ore reduction chamber of the kiln. A charge of ore isprovided in the reduction chamber and it is reduced to a higher state ofiron.

Examples of such prior art kilns are disclosed in US. Pat. Nos.1,216,667 issued Feb. 20, 1917, US. Pat. No. 2,091,850 issued Aug. 31,1937 and US. Pat. No.

3,182,980 issued May 11, 1965.

In the prior art kilns fuel and air are delivered through the nozzles bypiping supported on the exterior of the kiln or on the interior of thekiln. This piping is connected to the nozzles forv injecting the fueland air into the reduction chamber. In the prior art a mixture of bothfuel and air has been admitted through the nozzles at the same time orfuel is admitted through one nozzle and air admitted through a differentnozzle.

In certain instances it is desirable to admit only one fluid through anozzle when it is beneath the charge and only the other fluid when thenozzle is above the charge. As an example it is desirable in certaininstances to admit fuel to the reduction chamber through nozzles as theypass directly beneath the bed of the charge whereby the fuel flowsdirectly into the charge. When this nozzle has moved beyond the bed ofthe charge the fuel is shut off and no fluid is passing through thenozzle. At the same time air is admitted to the reduction chamber abovethe charge through additional nozzles. Before these air nozzles passbeneath the bed the air is turned off so that no fluid passes throughthese nozzles as theypass beneath the bed. From the above it can be seenthat quite a large number of nozzles are required. It is not unusual tohave as many as 300 nozzles in a rotary kiln of a 150 foot size. Furthermore these nozzles are exposed to extremely high temperatures in therange of 2,000 Fahrenheit. While the fluid is flowing through a nozzlethe fluid itself has a tendency to cool the nozzle. However when nofluid is passing through the nozzle it approaches the temperature withinthe reduction chamber thereby reducing the effective life of the nozzle.

It is therefore the intention and general object of this invention toprovide apparatus for reducing ore wherein the number of nozzlesrequired is reduced by one-half and the temperature of the nozzles isreduced by admitting fluid through the nozzles during a substantial partof the kiln rotation.

An additional object of the subject invention is to provide a rotarykiln with fluid distribution means which alternately delivers fuel orair to each nozzle at preselected points of rotation of the nozzlerelative to the kiln charge.

A more specific object of the subject invention is to provide a rotaryore reducing kiln of the hereinbefore described type wherein valve meansconnect both the fuel and air to a single nozzle for selective alternateflow of both fluids through the same nozzle.

An additional object of the subject invention is to provide a kiln ofthe hereinbefore described type wherein a single valve is utilized toalternately direct either fuel or air through the same nozzle atselected points of rotation of the kiln.

These and other objects of the subject invention will become more fullyapparent as the following description is read in light of the attacheddrawings wherein:

FIG. 1 is a side elevation of a portion of a kiln constructed inaccordance with the invention;

FIG. 2 is a section taken along the lines lI-II of FIG. 1 andadditionally showing means for operating the fluid distribution means;

FIG. 3 is a cross-section of a particular type of valve showing oneinlet port connected to the outlet port;

FIG. 4 shows the same valve as FIG. 3 with both inlet ports shut off;and

FIG. 5 shows the same valve with the other inlet port connected to theoutlet port.

Referring to the attached drawing the kiln shown herein for purposes ofillustration is provided with an elongated cylindrical body portion 6which defines a cylindrical reduction or combustion chamber 7. The shellor inner wall 8 of the kiln may be constructed of any suitablerefractory material such as firebricks. Any well-known means may beprovided for supporting and rotating the kiln. Since such means form nopart of this invention and are well known in the art they are not shownherein. A charge of ore generally designated 9 is shown in FIG. 2. Amain burner 11 is provided at the right-hand end of the kiln to preheatthe kiln.

A plurality of circumferentially spaced and axially spaced nozzles 12are provided about the surface of the kiln opening into the chamber 7.These nozzles may be constructed of any conventional manner and areprefand 16 respectively are also supported about the sur-- face of thekiln. Any conventional means in the form of a manifold (not shown) maybe provided to deliver I fuel and air to the conduits l4 and 16.

A fluid distribution means generally designated l7 connects therespective fuel and air conduits to the associated nozzles.- This fluiddistribution means may comprise a plurality of valves or as shown hereinfor purposes of illustration may comprise a single threeway valvegenerally designated 18 and fluid transfer conduit means 19 connectingthe outlet of the-valve 18 to the associated nozzles 12. The particularvalve 18 shown herein for purposes of illustration is more clearlydefined in FIGS.- 3 through 5. The valve consists of a valve body 20having two opposed inlet ports 21' and 22 and a single outlet port 23. Arotary plug 24 having a passageway 26 in the configuration shown isrotatably supported in the valve body and has a valve stem 27 attachedthereto and extending to the exterior of the valve body.

In many instances of reducing iron ore the fuel from conduit 14 isdelivered through the nozzles 12 while they are beneath the charge 9.Such fuel is only admitted while the nozzles are beneath the charge andair from conduit 16 is admitted through the same nozzles while they areabove the charge 9. To this end means are provided to operate the valve18 to effect this alternate delivery of fuel and air through each of thenozzles.

A preferred relatively inexpensive mechanical operating mechanism forcontrolling the flow of fuel and air into the chamber 7 is shown mostclearly in FIG. 2. It should be understood that while this controlmechanism is perfectly acceptable other means for operating the fluiddistribution means 17 could be employed such as a solenoid valveoperating hydraulic or air actuators. Referring to FIG. 2 a framegenerally designated 28 is provided about the kiln 6. This frame 28 isprovided with four strategically located trip means 29, 31, 32 and 33.

Each valve shaft 27 is connected to a cam plate 34 which is supportedfor rotation on brackets 36 connected to the exterior of the kiln forrotation therewith. Each cam plate 34 has four cams 37, 38, 39 and 41supported about the periphery thereof. The cams are spaced substantially90 from one another and are located to engage a particular trip meanswhen they are is turned on thereby having no period of time that a fluidis not flowing through the nozzles.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as folin the radially outermostposition relative to the axis of the kiln.

The operation of the apparatus will now be described. In order to assistin understanding the operation the trip means are identified on thedrawings starting with the trip 33 and progressing in the direction ofrotation of the kiln as air-off fuel-on fuel-off and airon. As astarting point assume that the cam 38 is about to contact the fuel-ontrip 29. This causes the valve 18 to move to the position shown in FIG.5 connecting the fuel conduits 14 to the associated nozzles through thetransfer conduits 19. As the kiln continues to rotate the cam 39 willcontact the trip 31 and the valve 18 will be in the off position shownin FIG. 4. As the kiln continues to rotate the cam 41 will contact thetrip 32 and the valve will be in the position shown in FIG. 3 permittingair to pass from the conduits 16 through the connected nozzles 12.Further rotation of the kiln causes cam 37 to contact trip 33 moving thevalve 18 to the opposite position as that shown in FIG. 4 interruptingthe flow of air to the nozzles. This process of alternate admission ofair and fuel through the nozzles will repeat as the kiln rotates.

From the above it can be seen that both fuel and air are alternatelyadmitted through each of the nozzles 12. This results in a reduction inthe number of nozzles required by one-half over those kilns which have aseparate nozzle for fuel and a separate nozzle for air. Furthermorebecause fuel or air is flowing through each nozzle during a substantialpart of the revolution of the kiln the nozzle temperature is reduced dueto the rela tively cooler fuel or air passing through the pipes on theexterior of the kiln. It should be understood that the control mechanismcould be so arranged that the air flowing through the nozzle is onlyturned off as the fuel lows:

1. An ore reducing kiln comprising; an elongated rotary cylindricalchamber having a charge of ore to be reduced contained therein; fluiddistribution means; a first fluid passage connected in fluidcommunication to said fluid distribution means; a second fluid passageconnected in fluid communication to said fluid distribution means; anozzle supported by said kiln for rotation with said cylindricalchamber, said nozzle being in fluid communication with said elongatedcylindrical chamber and with said fluid distribution means; and controlmeans associated with said fluid distribution means, one of said meanssupported by said cylindrical chamber for rotation therewith, saidcontrol means adapted automatically upon rotation of said cylindricalchamber to operate said fluid distribution means to alternately connectand disconnect said first and second fluid passage means to said nozzle.

2. A rotary ore reducing kiln comprising; an elongated cylindricalchamber having a charge of ore to be reduced contained therein; fluiddistribution means supported by said kiln for rotation therewith; firstfluid passage means supported by said kiln and connected in fluidcommunication to said fluid distribution means; second fluid passagemeans supported by said kiln and connected in fluid communication tosaid fluid distribution means; a nozzle supported by said kiln in fluidcommunication with said elongated cylindrical chamber and with saidfluid distribution means; and control means associated with said fluiddistribution means adapted automatically upon rotation of said kiln tooperate same to alternately connect and disconnect said first and secondfluid passagemeans to said nozzle.

3. The rotary ore reducing kiln set forth in claim 2 wherein said fluiddistribution means is at least one valve and said control means is a camplate connected to said at least one valve and-stationary trip means arepositioned to selectively engage said cam plate to operate said at leastone valve.

4. A rotary ore reducing kiln comprising:

an elongated cylindrical chamber having a charge to be reduced containedtherein; a nozzle supported by said kiln in fluid communication withsaid chamber, said nozzle rotating with said kiln and alternatelypassing beneath and above said charge; a rotary valve having first andsecond inlets and one outlet and capable of alternately connecting eachinlet to said outlet; first and second conduit means supported on theexterior of said kiln and connected respectively in fluid communicationto said first and second inlets;transfer conduit means connecting saidoutlet in fluid communication to said nozzle; a cam plate supported onsaid kiln and op eratively connected to said valve, said cam platehaving at least two cams; and trip means supported about said kiln forselective engagement by said cams, said cams and said trip means beingarranged to cause said valve to connect said first conduit to saidnozzle when said nozzle is beneath said charge and alternately toconnect said second conduit to said nozzle when said nozzle is abovesaid charge.

1. An ore reducing kiln comprising; an elongated rotary cylindricalchamber having a charge of ore to be reduced contained therein; fluiddistribution means; a first fluid passage connected in fluidcommunication to said fluid distribution means; a second fluid passageconnected in fluid communication to said fluid distribution means; anozzle supported by said kiln for rotation with said cylindricalchamber, said nozzle being in fluid communication with said elongatedcylindrical chamber and with said fluid distribution means; and controlmeans associated with said fluid distribution means, one of said meanssupported by said cylindrical chamber for rotation therewith, saidcontrol means adapted automatically upon rotation of said cylindricalchamber to operate said fluid distribution means to alternately connectand disconnect said fIrst and second fluid passage means to said nozzle.2. A rotary ore reducing kiln comprising; an elongated cylindricalchamber having a charge of ore to be reduced contained therein; fluiddistribution means supported by said kiln for rotation therewith; firstfluid passage means supported by said kiln and connected in fluidcommunication to said fluid distribution means; second fluid passagemeans supported by said kiln and connected in fluid communication tosaid fluid distribution means; a nozzle supported by said kiln in fluidcommunication with said elongated cylindrical chamber and with saidfluid distribution means; and control means associated with said fluiddistribution means adapted automatically upon rotation of said kiln tooperate same to alternately connect and disconnect said first and secondfluid passage means to said nozzle.
 3. The rotary ore reducing kiln setforth in claim 2 wherein said fluid distribution means is at least onevalve and said control means is a cam plate connected to said at leastone valve and stationary trip means are positioned to selectively engagesaid cam plate to operate said at least one valve.
 4. A rotary orereducing kiln comprising: an elongated cylindrical chamber having acharge to be reduced contained therein; a nozzle supported by said kilnin fluid communication with said chamber, said nozzle rotating with saidkiln and alternately passing beneath and above said charge; a rotaryvalve having first and second inlets and one outlet and capable ofalternately connecting each inlet to said outlet; first and secondconduit means supported on the exterior of said kiln and connectedrespectively in fluid communication to said first and second inlets;transfer conduit means connecting said outlet in fluid communication tosaid nozzle; a cam plate supported on said kiln and operativelyconnected to said valve, said cam plate having at least two cams; andtrip means supported about said kiln for selective engagement by saidcams, said cams and said trip means being arranged to cause said valveto connect said first conduit to said nozzle when said nozzle is beneathsaid charge and alternately to connect said second conduit to saidnozzle when said nozzle is above said charge.